Hot air is often used to melt solder when mounting/dismounting an electrical component. It is known that electrical components such as for example Surface Mount (SMT) packages may absorb moisture from the environment. The rapid increase in the temperature of the SMT package during a de-soldering operation may cause the absorbed moisture to superheat and turn to steam, delaminating the SMT Package and damaging the silicon chip inside the SMT package. Also, the rapid heating of an electrical component up to the melting temperature of the solder may damage the circuit board itself, or other nearby components. To address the potential problems, manufacturers of electrical components may provide suggested reworked procedures suggesting that the heating and hot air flow of the rework tool be staggered to first warm the component (and drive out moisture), then increase the heat delivered to the component over three or more stages until the reflow temperature of the solder is exceeded, at which point the component may be safely removed using a suction device.
In order to properly mount/dismount electrical components, the controller of a hot air rework tool may be preprogrammed with various temperature profiles, or rework control management data parameters, that may be pre-programmed into a memory of the controller. The rework control management data profiles may include temperature and airflow data points and elapsed time for each temperature set point. For example, a control management data profile may be divided into six (6) stages, and each stage has a set time and a target temperature. The control management data profiles may be preprogrammed so that they may be repeatedly used for identical or similar components. However, small changes in conditions, including for example the type or melt point of the solder, the characteristics of the substrate and the electrical component, and nearby components, may not suit the existing or preprogrammed control management data profiles, and could cause improper heating damaging the component or the substrate or nearby components.
Conventionally, even if the user noticed that the existing control management data will not work out, the user may only change the target temperatures or change the profile after all of the several stages of the heating process for the preprogrammed control management data profile have been completed, thus after the control management data profile finishes. If the user finds the control management data profile improper while the profile is executing, the user cannot change the setting. Since the user needs to wait until the selected profile finishes, it may take a long time to find an ideal target temperature profile.